Add command for pulling branch from alternate Git repository

hggithub.py

@@ -76,6 +76,14 @@ gitrepo = .hg/git.git
         )
 
 
+def hg_pull():
+    cmd(
+        "Updating Mercurial repository",
+        ["hg", "--config", "phases.new-commit=draft", "pull"],
+    )
+    cmd("Publishing master bookmark", ["hg", "phase", "-p", "master"])
+
+
 def _ghclone(git_fork_url, git_upstream_url, destination):
     working_dir, project_name = osp.split(destination)
     git_repo = osp.abspath(osp.join(working_dir, ".%s.git" % project_name))
@@ -105,12 +113,7 @@ def _ghpull(git_repo):
                 ["git", "fetch", "origin", "%s:%s" % (branch, branch)],
                 cwd=git_repo,
             )
-
-    cmd(
-        "Updating Mercurial repository",
-        ["hg", "--config", "phases.new-commit=draft", "pull"],
-    )
-    cmd("Publishing master bookmark", ["hg", "phase", "-p", "master"])
+    hg_pull()
 
 
 def _ghpush(git_repo, bookmark):
@@ -128,6 +131,18 @@ def _ghpush(git_repo, bookmark):
     )
 
 
+def _ghremote(git_repo, git_remote_url, git_branch, hg_bookmark):
+    if hg_bookmark == "master":
+        raise ValueError("Cannot replace master bookmark")
+    cmd(
+        "Fetching branch %s to %s from specified remote Git repository"
+        % (git_branch, hg_bookmark),
+        ["git", "fetch", git_remote_url, "%s:%s" % (git_branch, hg_bookmark)],
+        cwd=git_repo,
+    )
+    hg_pull()
+
+
 @command(
     "ghclone", [], _("git_fork_path git_upstream_path working_directory"), norepo=True
 )
@@ -163,3 +178,14 @@ def ghpush(ui, repo, bookmark, **opts):
         pass
     except ValueError as ex:
         print(ex)
+
+
+@command("ghremote", [], _("git_remote_path git_branch hg_bookmark"))
+def ghremote(ui, repo, git_remote_url, git_branch, hg_bookmark, **opts):
+    """Pull remote branch from alternate Git repository"""
+    os.chdir(repo.root)
+    git_repo = ui.config("gitrepo", "gitrepo")
+    try:
+        _ghremote(git_repo, git_remote_url, git_branch, hg_bookmark)
+    except CalledProcessError:
+        pass